/ Dictionary / Index B biennium: Meaning and Definition of Find definitions for: bi•en•ni•um Pronunciation: (bī-en'ē-um), [key] — pl. -en•ni•ums, -en•ni•a a period of two years. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. biennial bienvenu* Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language